A shock absorber for a motorbike as an example will be explained.
FIG. 10 are drawings showing a structure of a typical shock absorber (a no-cover type); FIG. 10(A) is an overall perspective drawing and FIG. 10(B) is an exploded perspective drawing.
A shock absorber 1 shown in FIG. 10 is one which is called as a no-cover type (or an exposed spring type) and is mainly used in road racing bikes and sport bikes. The shock absorber 1 is provided with a hydraulic damper 10 which has a cylinder 11 and a rod 13. The rod 13 projects from a distal end 11a of the cylinder 11 and moves forward and backward relative to the cylinder 11 in the length direction of the cylinder 11 being applied with buffer action. The cylinder 11 has a two-pronged attaching portion 12, provided with attach holes 12a, at its proximal end 11b. The rod 13 is formed with an attach ring 14 at its distal end. Usually, the attaching portion 12 of the cylinder 11 is attached to an axis arm side of a motorbike (a lower side of a motorbike) with a bolt and the attach ring 14 of the rod 13 is attached to a saddle side of the motorbike (an upper side of the motorbike) with a bolt.
A coil spring 15 is arranged around the damper 10 in a compressed state. One end 15a of the coil spring 15 presses against a flange portion 11c which is formed near the proximal end 11b of the cylinder 11 and the other end 15b of the coil spring 15 presses against a stopper 17 attached to a bottom portion 14a of the attach ring 14. The stopper 17 is detachably engaged with the bottom portion 14a of the attach ring 14 of the rod 13. As shown in FIG. 10(B), the coil spring 15 is detached from the rod 13 after detaching the stopper 17 from the rod 13.
The stopper 17 has a disk-like shape and is formed with a seating surface 18 at the periphery of the spring contact surface (the periphery of a back surface in FIG. 10(B)). The end 15b of the coil spring 15 is pressed against the seating surface 18. The stopper 17 has a circular opening 17a at its center and a slit 17b extending between the circular opening 17a and the periphery thereof. The slit 17b has a width larger than a diameter of the rod 13. The stopper 17 is engaged with the bottom portion 14a of the attach ring 14 of the rod 13 at the circular opening 17a thereof.
In an assembled state shown in FIG. 10(A), the stopper 17 is pressed against the bottom portion 14a of the attach ring 14 of the rod 13 with spring force of the coil spring 15. When the rod 13 moves backward to the cylinder 11, the stopper 17 pushes the end 15b of the coil spring 15. In an inside of the coil spring 15, a rubber dumper 19 is fitted on the middle of the rod 13. When the rod 13 is moved backward for a long distance to compress the coil spring 15 considerably, the rubber damper 19 is sandwiched between the stopper 17 and the distal end 11a of the cylinder 11 so as to exert damper action.
In such cases where such the shock absorber 1 is repaired from damages or the damper 10 is replaced owing to deterioration of oil in the damper 10 with age, the shock absorber 1 is detached from the motorbike, disassembled, repaired, assembled and then attached to the motorbike again. Also the shock absorber may be detached, in such cases where a damping ratio (a rate) of the damper 10 is adjusted or a vehicle height of the motorbike is adjusted.
An exemplary tool for disassembling the shock absorber 1 includes ones shown in FIGS. 16 to 18.
FIG. 16 is an overall perspective drawing showing an example of a conventionally used tool for disassembling the shock absorber.
FIG. 17 is a side drawing showing the disassembling tool shown in FIG. 16 to which the shock absorber shown in FIG. 10 is attached.
FIG. 18 is a side drawing showing a state in which the arm is pushed down from the state shown in FIG. 17 so as to detach the stopper from the disassembling tool.
The disassembling tool 100 shown in FIG. 16 is provided with a base 101. On one end of an upper surface (a left end of the surface in the figure) of the base 101, a L-shaped spring hold member 103 is attached. The spring hold member 103 has a base portion 104 which is attached to the base 101 with an attach pin 102 (shown in FIGS. 17 and 18) and an inserting portion 105 standing upright from the base portion 102. The inserting portion 105 is formed with a vertical slit 106 at its center. The spring hold member 103 is rotatable to the base 101 around the attach pin 102.
On another end (a right end in the figure) of the base 101, an arm 110 is rotatably attached. The arm 110 is a member made by folding a long plate to form one pair of supporting ends 110a and a distal free end 110b. The supporting ends 110a sandwich the end of the base 101 therebetween and are attached to the side walls of the base 101 with a bolt 107B and a nut 107N. The arm 110 rotates around the bolt 107B. Each of the supporting ends 110a is formed with a pin insert hole 110c into which each of pins 115 (a large diameter) and 116 (a small diameter) having different diameters is inserted. The pins 115 and 116 are connected each other by a ring 117. The pins 115 and 116 are used for holding the attaching portion 12 of the cylinder 11 of the damper 10 to the arm 110.
A way for disassembling the shock absorber 1 shown in FIG. 10 by using the disassembling tool 100 will be explained.
First, as shown in FIG. 17, the shock absorber 1 is placed on the base 101 with the cylinder 11 of the damper 10 being placed at a side of the arm 110 and the rod 13 being placed at a side of the spring hold member 103. Then, the attaching portion 12 of the cylinder 11 is set between the supporting ends 110a of the arm 110, and after aligning the attach holes 12a with the pin insert holes 110c of the arm 110, the pin 115 or the pin 116 selected on depending the diameter of the attach hole 12a is inserted thereto (the large diameter pin 115 is inserted, in FIG. 17). And, the rod 13 is set in the vertical slit 106 of the spring hold member 103, and, at the same time, the inserting portion 105 is inserted between the coils of the coil spring 15 (for example, between the second coil and the third coil). In this case, the spring hold member 103 rotates around the pin 102 so as to correspond to the orientation of the coil of the coil spring 15.
In this state, the shock absorber 1 is situated such that the cylinder 11 is held to the arm 110 with the pin 115 and the coil spring 15 presses against the inserting portion 105 of the spring hold member 103. On pushing down the arm 110 rotatively in the direction of an arrow α in FIG. 17, the cylinder 11 is pushed in the direction of an arrow β in FIG. 17 and then the whole of the damper 10 is moved in the direction of the arrow β. So, one end 15a of the coil spring 15, which presses against the flange portion 11c of the cylinder 11, is pushed accompanied with the movement of the cylinder 11. As a result, the coil spring 15 is compressed between the inserting portion 105 of the spring hold member 103 and the flange portion 11c. 
On further pushing down the arm 110 in the direction of the arrow α, as shown in FIG. 18, the damper 10 is moved in the direction of the arrow β further and the coil spring 15 is further compressed between the flange portion 11c of the cylinder 11 and the inserting portion 105 of the spring hold member 103. Consequentially, a gap L is formed between the end 15b of the coil spring 15 and the stopper 17 which is engaged with the bottom portion 14a of the attach ring 14. Then, the stopper 17 is moved toward the end 15b of the coil spring 15 so as to be disengaged from the bottom portion 14a and is detached from the rod 13 through the slit 17b. After detaching the stopper 17, the arm 110 is rotated to the initial position, then the distal end of the rod 13 is lifted upward and the coil spring 15 is detached from the spring hold member 103. Then, the coil spring 15 is detached from the rod 13. As a result, the shock absorber 1 is disassembled into the damper 10, the coil spring 15 and the stopper 17 (shown in FIG. 10(B)).
Tools or apparatuses used for compressing a spring are disclosed in the following literatures in addition to the disassembling tool 100 shown in FIGS. 16 to 18.
Tools and apparatuses for compressing a spring for automotive members are disclosed in Japanese published examined application No. S54-38360, Japanese published unexamined application Nos. S58-171274, H10-249751, utility model application No. S53-56658 and the like
Tools and apparatus for compressing a spring for valves are disclosed in U.S. Pat. No. 1,529,476, U.S. Pat. No. 1,346,416 and the like.